The lighting theory of light-emitting diode (LED), which is different from that of incandescent lamp, is to generate light by releasing the energy generated from the move of the electron between n type semiconductor and p type semiconductor. So the LED is called a cold lighting source. Furthermore, since LED has advantages as highly durable, long life-time, light weight, low power loss, nowadays LED is highly expected to be a new generation lighting device in the lighting market.
FIG. 1 is a diagram of a conventional optoelectronic element 100 including a substrate 10, a semiconductor stacked layer 12 disposed on the substrate 10, and at least an electrode 14 disposed on the semiconductor stacked layer 12, wherein from top to bottom the semiconductor stacked layer 12 includes a first conductive type semiconductor layer 120, an active layer 122, and a second conductive type semiconductor layer 124.
In the conventional optoelectronic element 100, the surface of the semiconductor stacked layer 12 is flat, and the refractive index of the semiconductor stacked layer 12 is different from that of the external environment, so the light emitted from the active layer has total internal reflection (TIR) easily.
Moreover, when the conventional optoelectronic element 100 is in operation, the current flows into the semiconductor stacked layer 12 via the electrode 14. Most of the current flows in the semiconductor stacked layer 12 by a shortest route, therefore the current distributes in the semiconductor stacked layer 12 unevenly, and the illumination efficiency of the optoelectronic element 100 is affected.
Besides, the optoelectronic element 100 can further connects to other elements to form an optoelectronic apparatus. FIG. 2 is a structure diagram of a conventional optoelectronic apparatus. As shown in FIG. 2, an optoelectronic apparatus 200 includes: a sub-mount 20 at least having a circuit 202; at least a solder 22 disposed on the sub-mount 20 to attach the optoelectronic element 100 on the sub-mount 20, and electrically connects the substrate 10 of the optoelectronic element 100 to the circuit 202; and an electrical connection structure 24 for electrically connecting the electrode 14 of the optoelectronic element 100 to the circuit 202 of the sub-mount 20, wherein the sub-mount 20 can be a lead frame or a mounting structure for circuitry planning of the optoelectronic apparatus 200 and for enhancing the heat-dissipation.